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Making Object VRs

Object VRs are interactive movies that allow the viewer to rotate a virtual object on the computer screen. They are useful in teaching, as rare or ephemeral subjects can be photographed when available, then scrutinized non-destructively by students at a later date. Making Object VRs requires some specialized equipment, Quick Time software, and some new Photoshop skills.

To create an Object VR you will need some sort of turntable. A cheap and useful one is the Pixie Manual Turntable made by Kaidan. If the object to be photographed is small, it can be mounted on the pedestal, and it if is large, the pedestal can be removed and the object placed directly on the turntable. The turntable has click stops at 10 degree intervals. Carefully center the object on the turntable. Choose an appropriate background and decide how the object should be lit (see Lighting Diagrams). I often use Side Lighting w/ Bounce Fill to highlight surface detail as the object rotates. Set up the camera on a tripod and carefully center the object in the viewfinder. It is helpful to spin the object around 360 degrees to make sure it is centered at all positions. Decide how many images you wish to make. 36 images (10 degree intervals) will give a very smooth rotation but you may find that 18 images (20 degree intervals) will suffice and be half the file size. When you've made these decisions, take a series of exposures (see Making a Good Exposure) rotating the turntable between each exposure. Be sure to use Manual exposure mode as you want each exposure to be the same and also set the White Balance to match the light source (not AUTO) because you don't want the camera shifting WB from picture to picture.

I generally set the image compression in the camera to the highest quality JPEG setting available. When the series of pictures is taken, download them to your computers hard drive. At this point it is very important to keep the files organized. I create a new folder on the hard drive for each specimen and within that folder download the camera images to a folder labeled something like "Camera". These will be your source images that can be returned to at a later date if needed.

Since these individual images will be used as frames in an animation, it is important that any changes made to them in Photoshop (Levels, Color Balance, Cropping, etc) be exactly the same. This would be very difficult and time consuming to do to all 36 images, but Photoshop has a nifty tool called "Actions" that will make this job much simpler.

Using Photoshop Actions

When you open the first of the 36 (or 18) pictures for the VR it will look something like this. The image will need to be rotated, cropped, and exposure adjusted. To do this exactly the same to all the images, we need to set up an "action" that Photoshop will automatically do to all the images. This action is really a miniprogram that you record and then apply to each picture. Actions are recorded in the Actions palette that is found as a tab behind the History palette. If you don't see either of these on the Photoshop desktop, turn them on in the Window menu. At this point, it is also advisable to creat a new empty folder in your specimen folder and label it something like "Fix". This is the folder that all the corrected files will be saved in when the action is being run.

Start out by opening just one of the series of pictures that need to be modified. To record an action, click the Create new action button at the bottom of the Actions palette. This will start recording every change made to that image. It is a good idea to do a rehearsal of all the changes before actually recording the action. This will force you to think about the changes you wish to make (see Photoshop-Basic Tools).

When the Create new action button is clicked, you will be asked to name the action. Pick a descriptive name, as over time lots of actions will be built up and you need to know which is which.

Make all the adjustments to the image. It's a good idea at this point to not fully crop the image because minor positioning changes may need to be made later to better center the object. In this situation changes were made using Crop, Levels, Curves, Unsharp Mask, and Shadow/Highlight. At this point save the image as a TIFF, using the Save As command. I convert the image from JPEG (from camera) to TIFF because many more alterations may need to be made to the images, and the TIFF format can be altered and resaved without degrading the image (see Image File Formats). When the action is completed, click the square button at the bottom left of the palette. This stops the recording. Close the image.

To apply this action to all the images in the "Camera" folder, go to File/Automate/Batch. This dialog box will open. At the top, under Play, choose the action you wish to run from the pull-down menu, in this case CUP-CH1923 (the designation for the fungus pictured). In the next section, Source, choose Folder from the pull-down and then navigate to your source folder using the Choose button. The folder you choose here, should be the one with the camera downloads that you named "Camera". I generally also check the Suppress Color Profile Warnings, to keep any mismatch in Color Profile between camera and computer from causing problems. Next, under Destination, choose Folder and navigate to the destination folder that has been set up called "Fix". If part of the action includes a Save As command (in this situation it does, because we used Save As to change from JPEG to TIFF) check the box Override Action "Save As" Commands (red arrow). Now click OK and watch the fun. Photoshop will open each file from the Source folder, make all the recorded changes, and save the fixed image to the destination folder.

Critical Alignment and Scales

No matter how careful you are setting up the object, it will seldom be perfectly in alignment. This will lead to the final Quick Time VR appearing jerky as the object jumps to different positions during playback. I use Photoshop to tighten up the alignment in the following way:

Choose one of the 36 images to set up as a standard. In this case I have chosen the picture of the fungus that fully faces front. Start an action. Pull a guide from the ruler on the left and place it at the middle of the image. Place two more guides on either side and equidistant from the middle guide. If you don't see rulers on the side and top of your image go to the View menu and click on Ruler. Stop the action and run it on the images in the "Fix" folder. This will place guides in exactly the same locations on all the images. In this case the Source folder and the Destination folder will both be the same and you will want to unclick the Override Action "Save As" Commands.

You can see that 2 images from different times in the rotation are not centered the same within the guide lines. In this situation I have decided to center the visible portion of each image within the guide lines. This will require shifting the image left or right until it is centered.

To do this open up each image in the "Fix" folder individually and Select All. Choose the move tool and use the arrow buttons on keyboard to center each image and resave. When all the images are done, set up an action and record the final cropping of the image and also clear all the guides (View/ Clear Guides). Now the "Fix" folder should contain TIFF images that are centered and cropped to the intended final proportion.

With scientific imagery, it is often important to include a scale with the specimen. The first step of this process is to photograph a scale at the same magnification as the specimen. I always take a 37th exposure for each VR that includes a scale. Crop the scale out of this image and drag it onto one of the images from the "Fix" folder. Using the scale (in this case a millimeter scale) place guides on the image where you want to draw the scale. When all the guides are drawn, drag the layer with the scale into the trash (in the Layers palette). This scale will have to be positioned in exactly the same location on all 36 images so again lets set up an action to do this.

Start recording a new action and use the Line and Type tools to draw and label the scale. Make sure that you have View/SnapTo/Guides clicked and the lines will stick to the guides. When all the lines and text are made, flatten the image (Layer/Flatten Image), clear the guides, and stop the action. Run the action on the images in the "Fix" folder and the scale will be drawn on all of them. At this point, we're almost ready to create the Quick Time movie, but the images must be sized to their final intended pixel dimensions. If this is done in Photoshop, the final image will be sharper than if it is done in Quick Time VR Authoring Studio. Determine what the final pixel dimensions of the VR should be. For web presentation this will be pretty small (400-600 pixels in longest dimension). In this example we will create a VR that is 400 pixels in the vertical dimension. Create a new folder in the specimen folder and name it 400Pix. Start an action, resize the image to 400 pixels vertically, Unsharp Mask, and Save As a JPEG with compression (I use 5 or 6). Stop the action and run (Source-Fix, Destination-400Pix, click Override "Save As" Commands).

Making Quick Time Movie

After all that preparation, we're finally ready to compile the VR movie. I use the program Quick Time VR Authoring Studio which is a Mac only program. Another program, VR Toolbox, is cross platform.

Open QTVR Authoring Studio and load (Add Files) the 36 finished JPEGs. The images will load in order by their number. In the upper left corner in Define Object say 36 columns at 10 degrees apart (18 columns at 20 degrees if you used 18 pictures). Under Output Files, click Object. Next click on the Settings button.

In the Compression Settings box choose a format (I use Photo-JPEG) from the pull-down menu. Next choose the Quality (compression). I generally choose a Medium setting if the QTVR is for the web and High if the QTVR is for direct viewing from a hard drive.

Next comes the Object Settings. If the QTVR is to rotate horizontally, check the Wrap box here. If the QTVR is to rotate vertically, check the Wrap box under Vertical controls. Check the Auto-play Views box if you want the VR to run automatically. In this case I checked this and set the Auto-play Speed to .2. The rest of the settings and those in the Playback tab can be left on the default settings.

In the File tab, you can title and fill in information about copyright, authoring, and other data about the specimen. This information will be saved with the QTVR and can be retrieved through the Quick Time Viewer. When all these setting are made, click OK, and then click the Make Object button on the main menu. You will be able to view the final VR. If it looks good, then save. If you want to make changes, go back to the Settings box and then remake the object until you're pleased.